Campaign manager Ed Rollins, who handled day-to-day operations, is now a senior adviser. Rollins, 68, cited his health as the reason for leaving the demanding manager post.

The staffing downgrade came after Rollins publicly acknowledged that Bachmann is having a hard time maintaining momentum in the wake of Texas Gov. Rick Perry’s entrance into the race. Perry bigfooted her straw poll win by declaring his candidacy the same day.

Kent Sorenson, Bachmann’s Iowa campaign chairman told The Des Moines Register tonight that Polyansky has indeed exited, but that it was the plan all along for Polyansky to stick with the campaign through the Aug. 13 straw poll.

“It was a question if he was going to stay on past the straw poll. I think that was left up for discussion,” Sorenson said.

And the decision over Rollins’ role “has been building over the last week,” Sorenson said. “He had a stroke last year, or a year and a half ago, and it’s not a nine to five job. It’s a 12, 14, 18-hour a day job.

“I think he just realized it’s a young man’s game. I’ve talked to Ed two or three times in last two days and he’s still on board with Michele in an advisory role but he’s just not able to travel.”

The changes won’t slow the campaign as it switches into caucus mode, Sorenson said.

Polyansky’s departure was tentatively planned, so “I think somebody’s trying to make a whole bunch out of nothing. When he came on I was told, ‘He’s here for the straw poll.'”

The news release says Team Bachmann is “expanding its focus on winning the Iowa caucuses and early primary states.”

Bachmann gave a written statement praising Rollins: “In less than 50 days and with fewer resources than other campaigns, Ed was the architect that led our campaign to a historic victory in Iowa. I am grateful for his guidance and leadership, and fortunate to retain his valuable advice even though his health no longer permits him to oversee the day-to-day operations of the campaign.”

Sorenson said all Rollins’ brain power and strategy savvy remains with the campaign.

Rollins signed on with the Bachmann campaign shortly before she announced June 13 during a live televised debate that she would seek the 2012 GOP nomination, and Polyansky was on board when she formally announced in Waterloo on June 26.

Bachmann in the news release tonight said of Nahigian: “Keith has played a vital role in the success we have had to date and I’m confident he can lead us to a strong finish in Iowa, New Hampshire, South Carolina and across the country.”

Perry is leading in Iowa, according to a new Rasmussen survey of likely Iowa GOP caucusgoers released today.

He’s the first choice for 29 percent, while Bachmann’s at 18 percent and former Massachusetts Gov. Mitt Romney is at 17 percent. Texas Rep. Ron Paul rang in at 14 percent. No other candidate had more than 4 percent.